Methods of this kind are already known from the state of the art. In such methods, probe heads are usually used in which the probe pin is moveably attached to the probe head in the three coordinate directions. For this purpose, the known probe heads include a probe head mechanical system in the interior thereof via which the probe pin can be deflected in the three coordinate directions. The probe head mechanical system usually has three guideways for this purpose. Each of the guideways permits the movement in one of three coordinate directions of the coordinate measuring apparatus. For this purpose, each of the three guideways is aligned parallelly to one of the movement directions of the coordinate measuring apparatus.
The deflections of the probe pin are measured by the measuring systems of the probe head. In order to incorporate these measured deflections of the probe pin into the coordinate system of the coordinate measuring apparatus, a transformation matrix was used in the past via which the measured measurement values of the probe pin deflection (deflection signals or probe head signals) were transformed into a coordinate system of the coordinate measuring apparatus. The individual parameters of this matrix were determined in preceding calibration operations.
A corresponding probe head, for which such a calibration operation was explained, is described in the article entitled “Multidimensional measuring probe head improves accuracy and functionality of coordinate measuring machines” by W. Lotze published in the journal “Measurement 13” on pages 91 to 97 (1994) (publisher: Elsevier Science B.V.). On pages 95 and 96 of this publication, a description is provided for the determination of the parameters of a corresponding matrix H for the two-dimensional case (the probe can only be moved in the xy-plane).
In recent times, and for various reasons, probe heads were used whose guideways no longer permit movement parallel to the coordinate directions of the coordinate axes of the coordinate measuring apparatus. For example, probes are used whose probe pin is linearly guided in the direction of its longitudinal axis; whereas, the probe pin is rotatably moveably journalled via a cardan joint for movement in the two other coordinate directions.
In the attempt to couple such a probe head to a coordinate measuring apparatus utilizing conventional transformation matrices, problems have developed insofar as the known methods for calibrating corresponding probe heads no longer converge.